In recent years, color photographic materials have made a marked progress in the increase of their photographic speed and in the improvement of image qualities which they can provide. The diversification of the image size (format) has also advanced. Under these circumstances, there has been created a growing demand for color photographic materials which can ensure higher photographic speed and higher image quality.
The image quality of photographs obtained by users, however, depends largely on whether or not the photographs undergo proper photographic processing. With respect to the photographic processing, diversification of facilities therefor (e.g., the spread of minilaboratory and over-the-counter processing), reduction of processing time and decrease in amounts of replenishers have rapidly proceeded. These processing conditions are in fact responsible for fluctuation in processing results.
Color photographic materials, especially color reversal materials, are greatly influenced by processing factors. In designing color photographic materials, therefore, it becomes an important problem to lessen the dependence of their performance on processing factors.
Such being the case, not only further increase in photographic speed and image quality but also reduction in performance deterioration due to processing factors are urgently required of color photographic materials.
On the other hand, dyes produced from conventional yellow, magenta and cyan couplers in silver halide color photographic materials had unnecessary side absorptions, and so they were apt to fail in satisfactory color reproduction. Thus, for compensating such dyes for their side absorptions, loads, including the use of colored couplers and the provision of excess interimage effect, have been imposed on photographic materials. Therefore, development of new couplers showing reduced side absorption have been tried.
As for the magenta dyes, there have been noted the improvement in hue by using pyrazoloazole magenta couplers instead of conventional 5-pyrazolone magenta couplers. Those couplers are disclosed, e.g., in U.S. Pat. No. 3,725,067, JP-A-60-172982 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-60-33552, JP-A-61-72238, and U.S. Pat. Nos. 4,500,630, 4,540,654 and 5,021,352.
The azomethine dyes produced from these couplers and oxidized products of color developing agents are known to be more favorable for color reproduction than those produced from 5-pyrazolone magenta couplers, because the former dyes have less side absorption in the vicinity of 430 nm than the later dyes.
However, pyrazoloazole magenta couplers have drawbacks such that their color formability is low, they are less resistant to fluctuation in their performance due to variation of processing factors, they have bad influences upon the storage stability of photographic materials and the color images produced therefrom are inferior in keeping property. Thus, it is the present situation that any wholly satisfactory usage of those couplers is not yet established.
Improvements in the color formability of couplers, the keeping property of color images, the extent of manifesting the effects of functional ingredients (including a color mixture preventive, DIR compounds and so on) and so on are well known to depend on the species of high boiling organic solvents generally used for dissolution and dispersion of couplers. Phthalate compounds and phosphate compounds are superior in solubility and dispersibility of couplers, affinity to colloids such as gelatin, hue of developed color images, stability, market price and so on. Therefore, such organic solvents have been prevailingly used. However, they cannot produce fine effects on solution of the aforementioned problems which pyrazoloazole magenta couplers have.
Hitherto, there have been proposed various arts of using pyrazoloazole magenta couplers. With the intention of heightening color formability, for instance, European Patent No. 0,486,929 discloses the method of using higher alcohols, while European Patent No. 0,491,317 discloses the method of using hydroxybenzoate. In addition, it is disclosed in European Patent No. 0,422,595 that those couplers can be rendered more resistant to the fluctuation in their performance due to variation of processing factors by the use of compounds containing a hydroxy group and an ester linkage.
Although the above-described art actually achieve some effect on reduction of performance fluctuation, it is still insufficient for the reduction of performance fluctuation arising from variation of processing factors present in the market. Accordingly, further improvement is required of the art as described above.
Further, JP-B-47-8745 (which corresponds to U.S. Pat. No. 3,650,759, and in which the term "JP-B" means an examined Japanese patent publication ) discloses 1,2-glycols as sensitizer for Roentgen films and black-and-white photographic materials. However, it has neither description such as "1,2-glycols contain an aliphatic or aryl group containing not less than 9 carbon atoms", nor suggestion that application of 1,2-glycols to color photographic materials will bring about improvements in color formability and performance fluctuation due to variation of processing factors.
Furthermore, JP-B-54-24289 discloses that 1,2-glycol is effective for stabilizing dispersion of photographic additives and inhibiting variation in hue during preservation under high temperature and high humidity conditions. However, JP-54-24289 is silence about the improvement in color forming ability and the pyrazoloazole coupler.